The First Opium War (1839–1842) was a conflict between Britain and the Qing Dynasty of China. It began after the Qing commissioner Lin Zexu had the opium held by British and American traders destroyed at Humen, near Canton (Guangzhou). It ended with the Treaty of Nanking, which gave Britain Hong Kong Island and opened five Chinese ports to British trade.
In five minutes: the short answer
Britain wanted to keep its trade with China open and to protect the opium trade, which Chinese law forbade. The Qing government wanted the trade stopped. In 1839 Lin Zexu destroyed the opium stock, and Britain answered by sending warships. British forces won most of the major clashes that followed. In August 1842, Qing envoys signed a treaty aboard a British warship anchored at Nanjing.
Historians still argue about when the war began. Some date it to September 1839, when fighting broke out near Kowloon. Others start the story in 1840, when the main British expedition set out. The core of the war runs from 1839 to the treaty of 1842, and that is the period this guide covers.
Why the Opium War started
Opium sat at the centre of the quarrel. The Qing government had restricted the drug since the 1700s, and an edict of 1796 banned the trade outright. Still, the trade continued and grew. Most foreign trade was confined to the port of Canton, and many officials in Beijing worried about silver leaving the country to pay for the drug.
For the wider context, see the topic hub Qing China, Japan and the West (1793–1912). Tensions rose through the 1830s. In 1834 Lord Napier, Britain's chief superintendent of trade, died of typhus at Macau in October, weeks after a confrontation with Qing officials had led to a temporary halt in British trade. In 1836 Charles Elliot became superintendent, and he would lead the British side in the first clashes.
In 1839 the Daoguang Emperor sent Lin Zexu to Canton with orders to end the trade. Sources give different dates for his arrival in early 1839. Lin wrote to Queen Victoria asking her to stop the opium trade. The letter is generally thought never to have reached her, and one account suggests it was lost in transit. In London, Parliament debated the war, and in late January 1840 the government survived a no-confidence motion by 21 votes.
The destruction of opium at Humen, 1839
In the spring of 1839 Lin pressed foreign traders to hand over their opium. Sources disagree on the amount. Some count about 20,000 chests; others give roughly 1,000 to 1,400 tonnes. Lin then had the opium destroyed in public at Humen Beach, starting on 3 June 1839. The work took about 23 days and ended around 25 June.
The destruction became a symbol on both sides. Many Chinese accounts treat it as a stand against a harmful drug. For British merchants it meant a heavy loss, and the British government pressed for compensation. The 6 million silver dollars that the 1842 treaty set aside for the confiscated opium shows how that grievance was eventually settled.
The first clashes, 1839–1840
The first serious clashes came near Kowloon. In July 1839 a Chinese man, Lin Weixi, was killed at Kowloon, which raised the temperature further. On 4 September 1839 a naval clash near Kowloon is listed as the war's start in some accounts. The Qing commander claimed a victory, but the Royal Navy was considerably stronger. Some historians prefer 1840 as the start instead.
On 3 November 1839 fighting broke out at Chuenpi (also spelled Chuanbi) when the British ship Royal Saxon tried to push toward Canton. Four Chinese war junks were destroyed, and both fleets withdrew. Qing officials reported a great victory, but modern accounts describe the Chinese ships as outclassed, with several disabled.
In June 1840 a much larger British expedition set out for China, meant to press the Qing government to meet British demands. The fighting then reached Macau. According to one account, Chinese soldiers seized a British clergyman, the Reverend Vincent Stanton, on 6 August 1840 while he was swimming, which caused uproar in the British community.
On 19 August 1840 British forces attacked the Barrier, the wall that crossed the narrow isthmus joining Macau to the mainland. The attackers numbered about 380 men, including Royal Marines, seamen and Bengal Volunteers. Estimates of the Qing garrison range from about 1,500 to 2,000. The British won, and the Qing troops withdrew.
Chuenpi, Hong Kong and the Bogue, 1841
On 7 January 1841 British forces attacked the Chuenpi forts in the Second Battle of Chuenpi. Steamers carried about 1,500 troops under Major Thomas Pratt to a point about two miles below the batteries, where they went ashore unopposed. The upper fort fell by about 10 a.m., and Royal Marines stormed the lower fort.
The same day the iron paddle steamer Nemesis attacked a fleet of about 15 Qing war junks under Admiral Guan Tianpei in Anson's Bay. Across the battle as a whole, 11 junks were destroyed. British losses were light: 38 wounded and no killed reported. Chinese losses are disputed. Qing records give 277 killed and 467 wounded, while the British commodore estimated 500 to 600 losses. The sources give no single agreed figure.
Diplomacy moved fast. The Convention of Chuenpi was drafted on 20 January 1841, but neither government ratified it. On 26 January Commodore Gordon Bremer took formal possession of Hong Kong Island and raised the Union Jack there. Elliot had been pressing for the island's cession at the same time, and the island was confirmed as British in the Treaty of Nanking.
Between 23 and 26 February 1841 British forces fought at the Bogue, the forts guarding the mouth of the Pearl River. They captured the remaining forts and won the battle. In the same year Canton (Guangzhou) agreed to pay a ransom of 6 million silver dollars, which some accounts later count within the treaty indemnity.
Amoy, Chusan and the road to the Yangtze, 1841–1842
After Hong Kong, British forces moved up the coast. They took Amoy (Xiamen) in August 1841; one source dates the main fighting to 26 August. On 1 October 1841 they retook Chusan (Zhoushan), where the Qing had reinforced the defences. Chinhai (Zhenhai) fell later in October, and Ningbo followed; one account says it fell without resistance.
The campaign continued in 1842. A British plan records operations at Tsekee (Cixi), near Ningbo, on 15 March 1842. One source adds that a Qing counterattack that month was beaten back. The main British force then turned to the Yangtze.
By July 1842 British forces had reached Chinkiang (Zhenjiang), where the Grand Canal meets the Yangtze, and blocked the river route. On 21 July about 6,900 British troops under Hugh Gough attacked the city. The defenders were Manchu and Mongol Bannermen and Green Standard troops; estimates put the Qing force at about 3,000 to 4,300. British losses were 37 killed and 128 wounded. A 19th-century estimate gives Qing losses of about 1,000 killed or wounded.
Accounts of the aftermath describe many Manchu defenders and their families dying by suicide as the city fell. The commander, Hai Ling, is also said to have died this way, though sources disagree on the details. The numbers are unclear, so historians treat them with caution.
The Treaty of Nanking, 1842
The Treaty of Nanking was signed on 29 August 1842 aboard HMS Cornwallis, anchored in the Yangtze at Nanjing. Henry Pottinger signed for Britain. Qing commissioners Qiying and Yilibu signed for the Qing government. The main terms were:
- Hong Kong Island was ceded to Britain in perpetuity.
- Five ports were opened to British trade: Canton (Guangzhou), Xiamen (Amoy), Fuzhou, Ningbo and Shanghai.
- An indemnity was set and paid in instalments over three years. The breakdown was 6 million silver dollars for the confiscated opium, 3 million for merchants' debts and 12 million for war costs, a total of 21 million. Some accounts add the 6 million Canton ransom to reach 27 million.
- British subjects gained extraterritoriality, which meant they were tried under British rather than Chinese law.
The Daoguang Emperor ratified the treaty on 27 October 1842 and Queen Victoria on 28 December 1842. The two sides exchanged ratifications at Hong Kong on 26 June 1843. A supplementary Treaty of the Bogue followed in 1843; the main accounts give only the year.
What the war changed
The Treaty of Nanking is often described as the first of the “unequal treaties” that China signed with Western powers. Hong Kong gave Britain a permanent base on the China coast, and the new ports became places where foreign merchants and officials lived under their own law.
Historians debate the war's place in history. Many consider 1839 the start of modern Chinese history, because the war exposed the limits of Qing military power and set a pattern for the treaties that followed. The technology gap is part of that story. The iron steamer Nemesis could work in rivers where larger warships could not, which helps explain how lopsided the fighting on the water was.
What exams ask
For AP World History and similar courses, expect questions on three points. First, causes: the opium trade, the drain of silver and the dispute over trade rules. Second, the Humen destruction and the British response that followed. Third, significance: the Treaty of Nanking and the start of the unequal treaty system. Strong answers explain why the treaty's terms, such as Hong Kong, the five ports, the indemnity and extraterritoriality, mattered beyond 1842.
Read next
These related FiveMinRead pages show what came before and after the war.
- Causes of the Opium War: how trade, trade rules and diplomacy built toward the 1839 crisis.
- The Taiping Rebellion (1850–1864): a major rebellion that began eight years after the treaty.
- The Boxer Rebellion (1899–1901): a later uprising against foreign influence in China.
